This thesis has used building recording techniques, documentary research and oral history testimonies to explore how concepts of the modern and new between the 1870s and 1930s shaped the urban built environment, through the study of a particular kind of infrastructure that was developed to meet the needs of expanding cities at this time – social (or municipal) housing – and how social housing was perceived and experienced as a new kind of built environment, by planners, architects, local government and residents. This thesis also addressed how the concepts and priorities of the Victorian and Edwardian periods, and the decisions made by those in authority regarding the form of social housing, continue to shape the urban built environment and impact on the lived experience of social housing today. In order to address this, two research questions were devised: • How can changing attitudes and responses to the nature of modern life between the late nineteenth and early twentieth centuries be seen in the built environment, specifically in the form and use of social housing? • Can contradictions between these earlier notions of the modern and new, and our own be seen in the responses of official authority and residents to the built environment? The research questions were applied to three case study areas, three housing estates constructed between 1910 and 1932 in Birmingham, London and Liverpool. During the course of answering these research questions, three further themes have arisen, which have broader relevance beyond this thesis: • How to interpret buildings that have a life extending beyond their original purpose. • The practice of contemporary archaeology as it relates to the built environment • How new kinds of environments are created and experienced, and how this can be investigated through material evidence.